Balance Question on House Rule

[BardicDuelist]

I recently read in annother thread a house-rule that I thought sounded interesting. It said that all characters gain 1/2 of their BAB to their AC. Since I don't like the defense bonus variant form UA, I thought this might work for me. My question is is how abused can this be to make a character untouchable?
Should it stack with armor? Should it apply to touch, flat-footed, or both?
I think it would be reasonable to make it apply to touch, but not stack with armor, but then would it make it impossible for a wizard to hit with a ray-spell since his BAB is so low?

Also, with the monsters who are "balanced" as far as their AC goes, wouldn't this make them considerably more difficult to hit?

It sounds like a good idea to me, but I would like to bounce these possible balance issues off the wonderful people here.

[Fualkner Asiniti]

Hmm... Yes, quite broken if applied to monsters. However, this makes sence only for monsters with actual weapons. Why? Take a look. BAB. I'd assume that this means you're actively parrying, and thus are adding defense to yourself. Thus, you have an accurate description of someone parrying blows. However, I'm not sure if this is balanced, and I need to sleep. However, this is an interesting rule.

[ForzaFiori]

If your gaining this from being able to Parry, then it should apply to regular AC, and not touch or flat-footed, since if u only need to be touched, then blocking is just gonna make whatever it is touch you, and you dont have the ability to react when your caught flat-footed. It should also only apply when wielding a weapon (maybe when unarmed if u have IUS)

[BardicDuelist]

If your gaining this from being able to Parry, then it should apply to regular AC, and not touch or flat-footed, since if u only need to be touched, then blocking is just gonna make whatever it is touch you, and you dont have the ability to react when your caught flat-footed. It should also only apply when wielding a weapon (maybe when unarmed if u have IUS)

I was thinking that, until I saw somthing on eskrima. You could theoretically block an opponent's forearm if the hand held the attack (such as shocking grasp) and keep yourself from being hit, though I guess that could make a feat instead.

You're right, it wouldn't affect rays though.

Should this only apply to melee?

[nerulean]

I don't see any reason it shouldn't apply to touch. If you consider BAB to represent basic combat savvy, then the bonus to AC could represent an ability to dodge blows as well as deflect them. Yes, the dex bonus represents this to some extent, but 10th level fighter well versed in combat would have more chance of reading an opponent, working out which way his sword was going and getting the heck out of the way than a 1st level fighter, or a 10th level wizard.

At any rate, definitely shouldn't get this bonus to FF AC.

[Tormsskull]

Could you describe what it is that this Houserule is intended to do? That might make it easier to justify what it should apply to, if it makes sense, etc.

[nerulean]

If the reasoning is anything like my reason for introducing class defence from UA, it's because the AC rules are irritatingly flat. Through training and experience, D&D allows you to increase just about every aspect of a character's prowess, be it magical or physical, but the one thing he can never do of his own accord is get better at avoiding hits in a fight, short of waiting eight levels to add two points to his dex for a measly single point of AC. Adding an increasing bonus means he isn't dependent upon a plethora of daft magic items to avoid horrible death every time he gets into combat.

[BardicDuelist]

If the reasoning is anything like my reason for introducing class defence from UA, it's because the AC rules are irritatingly flat. Through training and experience, D&D allows you to increase just about every aspect of a character's prowess, be it magical or physical, but the one thing he can never do of his own accord is get better at avoiding hits in a fight, short of waiting eight levels to add two points to his dex for a measly single point of AC. Adding an increasing bonus means he isn't dependent upon a plethora of daft magic items to avoid horrible death every time he gets into combat.

Well put. The only way to currently make your AC scale with your level is with comabt expertise.

[Deesix]

I've toyed with something like this for a while, in various systems. I like to think people parry in combat, but D&D really doesn't cover that. What I'd do is have the option to give up an attack and add 1/2 the BAB of the attack to AC against a single melee attack. But that's just me.

[Matthew]

You have a couple of choices with this really. It's usually intended for Low Magic Games, where it takes the place of the usual magical Bonuses that a Character gains to AC from Magical Items, in which case it stacks with everything else you use for AC. Sometimes, DMs allow it to work in Melee always, but only for Ranged Combat if you have a Shield.

The second method is to treat it as a supplemental Armour Class equal to 10 + Base Attack Bonus/Attack Bonus. You use the highest Armour Class you possess. This is basically similar to the often discussed 'Active Parry' Rule, but instead of rolling 1D20 you 'take 10'.

Whether you use (0.5 x BAB) or (1.0 x BAB) depends on how much magic you are using, which rule you use and whether you use Armour as Damage Reduction.